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    <title>Document</title>
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    <script>
        // for (var i = 0; i <= 50; i++) {
        //     if (i % 2 === 0) {
        //         console.log(i); 
        //     }
        // }
        // 判断0-50之间的偶数
        // for (var i = 0; i <= 50; i += 2) {
        //     console.log(i);
        // }

        // 判断25-50之间的奇数
        // for (var i = 25; i <= 50; i += 2) {
        //     console.log(i);
        // }
        
        // 打印hello9~hello0
        for (var i = 99 ; i >= 0; i--) {
            console.log(`hello${i}`);
        }
        for (var i = 0 ; i < 100; i++) {
            console.log(`hello${i}`);
        }
        
    </script>
</body>
</html>